get_category_parents到数组wordpress

Ok So I'm using wordpress and PHP.

Basicly I get a chosen category from a dropdown menu. I then find it's parents.

But then comes the part where I seem to fail. The output of $parents is a string with the names instead of the ID's.

So I try to get each word from the string into an array. And loop through them and convert them to their ID number.

I commented out where it doesnt seem to work. What am I doing wrong?

//Create array
$categoriesArray = [];

//Get choice from wp-dropdown
$selected_val = $_POST['cat'];

//Get parents from choice divided by (this seems to output a string)
$parents = get_category_parents( $selected_val, true, ',' );

/*
//Make array from string
$categoriesArray = explode(",",$parents);

for ($i = 0; $i < count($categoriesArray); $i++) {
{
    $categoriesArray[$i] = get_cat_ID($categoriesArray[$i]);
}
*/

//the array should look something like this.
//$categoriesArray = ["21","44"];

It had to do with the name of the category. I needed to use the slug instead of the name.

Here is my code that works. I can now make a new post and give it a category with their parents included!

//Create array
$categoriesArray = [];

//Get choice from wp-dropdown
$selected_val = $_POST['cat'];

//Get parents from choice divided by ,
$parents = get_category_parents( $selected_val, true, ',',false);

//Make array from string
$categoriesArray = explode(",",$parents);
for ($i = 0; $i < count($categoriesArray); $i++)
{
    $categoriesArray[$i] = get_cat_ID($categoriesArray[$i]);
}

try this,

function get_level($cat, $level = 0)
{
if ($cat->category_parent == 0) {
    return $level;
} else {
    $level++;
    $cat = get_category($cat->category_parent);
    return get_level($cat, $level);
}

}

if (is_category()) {
$cat = get_query_var('cat');
$your_cat = get_category($cat);

echo get_level($your_cat);
}